(countable) A particular posted letter or package which is delivered in this manner; a particular act of conveying such letters or packages to one or more recipients.

(countable and uncountable, idiomatic, by extension, sometimes humorous) Somethingâ€”whether desirable or undesirableâ€”which is intentionally given to a specific individual or which an individual receives rapidly and unexpectedly; the personalized, direct quality of the transmission of such an item.